2012/08/17 by Wei‐Qiang Ji, Wei-Qiang Ji, Fu‐Yuan Wu +5 · 1 citation
Earth and Planetary Sciences · #Geological and Geochemical Analysis #High-pressure geophysics and materials #earthquake and tectonic studies
paper · doi:10.1086/666742
This article presents zircon U-Pb and Hf isotope data, together with the whole-rock major- and trace-element composition, of Early Carboniferous granitoids newly identified from the Jiacha and Langxian areas in the southern Lhasa terrane, southern Tibet. The Jiacha rocks are monzogranites that yield zircon U-Pb ages of 347–345 Ma and εHf(t) values from −5.4 to −4.9. The Langxian rocks are granodiorites with slightly older zircon U-Pb ages of 355–352 Ma and lower εHf(t) values from −6.8 to −6.5. Our data suggest that these granitoids were generated largely by reworking of Paleoproterozoic ( Ga) basement materials. In conjunction with literature data, it is further argued that the southern and central parts of the Lhasa terrane, separated by the Sumdo eclogite belt, should have been an integrated block before the late Paleozoic. Our study supports the notion that the Lhasa terrane was derived from the northern margin of Gondwanaland, in association with formation of at least two stages of Tethyan Ocean basins, now exposed as the Sumdo belt and the Indus-Tsangpo suture.